create field trial config for new webstore navigation throttler

Bug: 399135314

Change-Id: I8e3db81c992dd6469606f9bcbaeb3027662ef440
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6307042
Reviewed-by: Owen Min <zmin@chromium.org>
Reviewed-by: Igor Ruvinov <igorruvinov@chromium.org>
Commit-Queue: marissa shen <marissashen@google.com>
Cr-Commit-Position: refs/heads/main@{#1425832}

testing/variations/fieldtrial_testing_config.json

@@ -5068,6 +5068,24 @@
             ]
         }
     ],
+    "ChromeWebStoreNavigationThrottle": [
+        {
+            "platforms": [
+                "chromeos",
+                "linux",
+                "mac",
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "ChromeWebStoreNavigationThrottle"
+                    ]
+                }
+            ]
+        }
+    ],
     "ChromeWideEchoCancellation": [
         {
             "platforms": [